City and County of San Francisco v. EPA

604 U.S. 334

• Court: Supreme Court of the United States
• Decided: March 4, 2025
• Docket: 23-753
• Status: Published

Opinion

PRELIMINARY PRINT

Volume 604 U. S. Part 1 Pages 334–368

OFFICIAL REPORTS OF

THE SUPREME COURT March 4, 2025

REBECCA A. WOMELDORF reporter of decisions

NOTICE: This preliminary print is subject to formal revision before the bound volume is published. Users are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, pio@supremecourt.gov, of any typographical or other formal errors. 334 OCTOBER TERM, 2024

Syllabus

CITY AND COUNTY OF SAN FRANCISCO, CALIFORNIA v. ENVIRONMENTAL PROTECTION AGENCY certiorari to the united states court of appeals for the ninth circuit No. 23–753. Argued October 16, 2024—Decided March 4, 2025 Under the Clean Water Act (CWA), 33 U. S. C. § 1251 et seq., the Environ- mental Protection Agency (EPA) and authorized state agencies issue permits that impose requirements on entities that wish to discharge “pollutants” into the waters of the United States. A critical component of the CWA regulatory scheme is the National Pollutant Discharge Elimination System (NPDES), which makes it unlawful to discharge pollutants into covered bodies of water unless authorized by permit. EPA v. California ex rel. State Water Resources Control Bd., 426 U. S. 200, 205. These permits typically include “effuent limitations” on dis- charges that restrict the “quantities, rates, and concentrations of chemi- cal, physical, biological, and other constituents.” § 1362(11). Failure to comply with permit limitations exposes permittees to civil penalties and even criminal prosecution. §§ 1319(c) and (d). Under what is known as the “permit shield” provision, however, an entity that adheres to the terms of its permit is deemed to be compliant with the Act. § 1342(k). This case involves a challenge to “end-result” requirements—permit provisions that do not spell out what a permittee must do or refrain from doing but instead make a permittee responsible for the quality of the water in the body of water into which the permittee discharges pollutants. The City of San Francisco operates two combined waste- water treatment facilities that process both wastewater and stormwa- ter. Combined Sewer Overfow (CSO) Control Policy, 59 Fed. Reg. 18689; 75 F. 4th 1074, 1082 (CA9). During periods of heavy precipita- tion, the combination of wastewater and stormwater may exceed the facility's capacity, and the result may be the discharge of untreated water, including raw sewage, into the Pacifc Ocean or the San Francisco Bay. 59 Fed. Reg. 18689; EPA, Offce of Water, Combined Sewer Over- fows: Guidance for Permit Writers, p. 1–1; 75 F. 4th, at 1082–1083. In 1994, the EPA adopted its CSO Control Policy, which requires munici- palities with combined systems to take prescribed measures and to de- velop and implement a Long-Term Control Plan, and provides for a two- phase permitting process. 59 Fed. Reg. 18691, 18696. Cite as: 604 U. S. 334 (2025) 335

For many years, San Francisco's NPDES permit for its Oceanside facility was renewed without controversy, but in 2019, the EPA issued a renewal permit that added two end-result requirements. 75 F. 4th, at 1084–1085. The frst of these prohibits the facility from making any discharge that “contribute[s] to a violation of any applicable water qual- ity standard” for receiving waters. Id., at 1085. The second provides that the City cannot perform any treatment or make any discharge that “create[s] pollution, contamination, or nuisance as defned by California Water Code section 13050.” Ibid. (internal quotation marks omitted). San Francisco argued that the end-result requirements exceed the EPA's statutory authority, but the Ninth Circuit denied the City's peti- tion for review. The court held that § 1311(b)(1)(C) authorizes the EPA to impose “any” limitations ensuring applicable water quality standards are satisfed in a receiving body of water. Held: Section 1311(b)(1)(C) does not authorize the EPA to include “end- result” provisions in NPDES permits. Determining what steps a per- mittee must take to ensure that water quality standards are met is the EPA's responsibility, and Congress has given it the tools needed to make that determination. Pp. 344–355. (a) Not all “limitations” under § 1311 must qualify as effuent limita- tions. While §§ 1311(b)(1)(A) and (B) refer to “effuent limitations,” § 1311(b)(1)(C) refers to “any more stringent limitation.” This distinc- tion shows that Congress intentionally authorized limitations beyond effuent limitations because “it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion” of lan- guage in a statute. Russello v. United States, 464 U. S. 16, 23 (internal quotation marks omitted). Other CWA provisions support this by re- ferring to “effuent limitations and other limitations” under § 1311. See, e.g., §§ 1341(d), 1365(f). Moreover, San Francisco's interpretation would either invalidate widely accepted narrative permit provisions or require an improbably broad reading of “effuent limitation.” Pp. 344–345. (b) Section 1311(b)(1)(C) does not authorize permit requirements con- ditioning compliance on receiving water quality. The provision's text, structure, and context support this interpretation. Pp. 345–355. (1) The terms “limitation,” “implement,” and “meet” in § 1311(b) (1)(C) suggest the EPA must set specifc rules permittees must follow to achieve water quality goals. A “limitation” is a “restriction . . . im- posed from without,” not an end-result requirement leaving permittees to determine necessary steps. Webster's Third New International Dic- tionary 1312. When a provision tells a permittee that a particular end result must be achieved, the direct source of the restriction comes from 336 CITY AND COUNTY OF SAN FRANCISCO v. EPA

within, not “from without.” To “implement” standards requires “con- crete measures,” not simply mandating achievement of results. Id., at 1134; § 1311(b)(1)(C). A limitation that is “necessary to meet” an objec- tive is most naturally understood to mean a provision that sets out ac- tions that must be taken to achieve the objective. Pp. 346–348. (2) The pre-1972 Water Pollution Control Act (WPCA) contained a provision that allowed direct enforcement against a polluter if the qual- ity of the water into which the polluter discharges pollutants failed to meet water quality standards. See Federal Water Pollution Control Act, ch. 758, §§ 1, 2(d)(1), 2(d)(4), 2(d)(7), 62 Stat. 1155, 1156–1157. But Congress deliberately omitted such provisions when overhauling the law in 1972. Instead, the CWA imposes “direct restrictions” on polluters rather than working backward from pollution to assign responsibility. EPA, 426 U. S., at 204. The Government's interpretation would undo what Congress plainly sought to achieve when it scrapped the WPCA's backward-looking approach. Pp. 348–349. (3) Two features of the broader statutory scheme further support this conclusion. First, end-result requirements would negate the CWA's “permit shield” protecting compliant permittees from liability. Second, EPA's interpretation provides no mechanism for fairly allocat- ing responsibility among multiple dischargers contributing to water quality violations. Pp. 350–352. (c) The Agency has adequate tools to obtain needed information from permittees without resorting to end-result requirements. Its reliance on the Combined Sewer Overfow Policy is misplaced as that policy au- thorizes narrative limitations but not end-result requirements. And concerns about disrupting general permits are unfounded given that narrative limitations remain available. Pp. 352–355. 75 F. 4th 1074, reversed.

Alito, J., delivered the opinion of the Court, in which Roberts, C. J., and Thomas and Kavanaugh, JJ., joined, in which Gorsuch, J., joined as to all but Part II, and in which Sotomayor, Kagan, Barrett, and Jack- son, JJ., joined as to Part II. Barrett, J., fled an opinion dissenting in part, in which Sotomayor, Kagan, and Jackson, JJ., joined, post, p. 356.

Tara M. Steeley argued the cause for petitioner. With her on the briefs were David Chiu, Yvonne R. Meré, David S. Louk, John S. Roddy, Estie M. Kus, Andrew C. Silton, John C. Cruden, and Richard S. Davis. Frederick Liu argued the cause for respondent. With him on the brief were Solicitor General Prelogar, Assistant Cite as: 604 U. S. 334 (2025) 337

Opinion of the Court

Attorney General Kim, Deputy Solicitor General Stewart, Meghan E. Greenfeld, and Steven M. Neugeboren.* Justice Alito delivered the opinion of the Court. Under the Clean Water Act (CWA), 86 Stat. 816, 33 U. S. C. § 1251 et seq., the Environmental Protection Agency (EPA) and authorized state agencies1 may issue permits that im- *Briefs of amici curiae urging reversal were fled for the Hayden Area Regional Sewer Board by Preston N. Carter and Morgan D. Goodin; for the Local Government Legal Center et al. by J. G. Andre Monette and Amanda Karras; for the National Association of Home Builders et al. by John A. Sheehan, Thomas Ward, and Prianka Sharma; for the National Mining Association et al. by Misha Tseytlin, Michael A. Tilghman II, Ellen Steen, Travis Cushman, Andrew R. Varcoe, Stephanie A. Maloney, Michael C. Formica, and Elizabeth Milito; and for Public Wastewater and Stormwater Agencies et al. by David Y. Chung, Elizabeth B. Dawson, Amanda E. Aspatore, Hilary Meltzer, F. Paul Calamita III, and Melissa A. Thorme. Briefs of amici curiae urging affrmance were fled for the State of California by Rob Bonta, Attorney General of California, Michael J. Mon- gan, Solicitor General, Christopher D. Hu, Deputy Solicitor General, Tracy L. Winsor, Senior Assistant Attorney General, Russell B. Hildreth, Super- vising Deputy Attorney General, and Marc N. Melnick and Bryant B. Cannon, Deputy Attorneys General; for the State of Washington et al. by Robert W. Ferguson, Attorney General of Washington, Kelly T. Wood, and Peter B. Gonick, Deputy Solicitor General, by Andrea Joy Campbell, At- torney General of Massachusetts, and Helen Yurchenco and Emily Mitch- ell Field, Assistant Attorneys General, and by the Attorneys General for their respective jurisdictions as follows: William Tong of Connecticut, Brian L. Schwalb of the District of Columbia, Kwame Raoul of Illinois, Aaron Frey of Maine, Anthony G. Brown of Maryland, Dana Nessel of Michigan, Keith Ellison of Minnesota, Matthew Platkin of New Jersey, Ellen F. Rosenblum of Oregon, Michelle A. Henry of Pennsylvania, and Josh Kaul of Wisconsin; for Environmental and Community Organizations by Kirti Datla, Benjamin Chagnon, and Linnet Davis-Stermitz; for the Orange County Coastkeeper by Sarah J. Spinuzzi; and for Small Business Owners and Operators by Keith P. Richard. 1 See 33 U. S. C. § 1342(b). The provision at issue in this case, § 1311(b)(1)(C), applies equally to federal and state permits, but for con- venience, we refer only to the EPA when referring to the scope of permit- ting authority under that provision. 338 CITY AND COUNTY OF SAN FRANCISCO v. EPA

pose requirements on entities that wish to discharge “pollut- ants” (a broadly defned term) 2 into the waters of the United States.3 Permits issued by these agencies include what the CWA calls “effuent limitations,” that is, provisions that specify the quantities of enumerated pollutants that may be discharged.4 It is also common for permits to set out other steps that a discharger must take. These may include test- ing, record-keeping, and reporting requirements, as well as requirements obligating a permittee to follow specifed prac- tices designed to reduce pollution. None of these so-called narrative requirements is at issue here. Instead, this case involves provisions that do not spell out what a permittee must do or refrain from doing; rather, they make a permittee responsible for the quality of the water in the body of water into which the permittee discharges pollutants. When a permit contains such requirements, a permittee that punctiliously follows every specifc require- ment in its permit may nevertheless face crushing penalties if the quality of the water in its receiving waters falls below the applicable standards. For convenience, we will call such provisions “end-result” requirements. The permittee in this case is a wastewater treatment facil- ity owned by San Francisco. For the past fve years, the facility's permit has included two end-result requirements, and if those provisions are upheld, the City could be heavily penalized even though it was never put on notice that it was obligated to take any specifc step other than those it under- took. San Francisco argues that the end-result provisions in its permit are not authorized by the CWA, and its position is supported by many other similarly situated cities, includ- ing New York, the District of Columbia, Boston, and Buffalo, as well as national and state associations whose members

2 § 1362(6). 3 § 1362(7). 4 § 1362(11). Cite as: 604 U. S. 334 (2025) 339

collectively “provide wastewater and stormwater services to the majority of [the people in this country whose homes are connected to sewers].” 5 We hold that the two challenged provisions exceed the EPA's authority. The text and structure of the CWA, as well as the history of federal water pollution legislation, make this clear. And resorting to such requirements is not necessary to protect water quality. The EPA may itself de- termine what a facility should do to protect water quality, and the Agency has ample tools to obtain whatever informa- tion it needs to make that determination. If the EPA does its work, our holding should have no adverse effect on water quality. I A To understand the issue before us, it is helpful to take a brief look back at the history of federal water pollution legislation. For most of the Nation's history, the Federal Government played a secondary role in this feld. See Sackett v. EPA, 598 U. S. 651, 659 (2023). In 1948, however, Congress passed the Federal Water Pollution Control Act (WPCA), ch. 758, 62 Stat. 1155, which represented a cautious expansion of federal authority. K. Murchison, Learning From More Than Five- and-a-Half Decades of Federal Water Pollution Control Leg- islation: Twenty Lessons for the Future, 32 Boston College Env. Aff. L. Rev. 527, 530–531 (2005). The WPCA reaf- frmed the long-accepted principle that “controlling water pollution” was primarily a state responsibility, but it also declared that the pollution of certain interstate waters had become “a public nuisance” and was “subject to abatement” in a suit brought by the Attorney General on behalf of the United States. §§ 1, 2(d)(1), 2(d)(4), 2(d)(7), 62 Stat. 1155– 1157. 5 Brief for Public Wastewater and Stormwater Agencies et al. as Amici Curiae 2. 340 CITY AND COUNTY OF SAN FRANCISCO v. EPA

Over the next 24 years, the WPCA was amended numer- ous times,6 and the federal role gradually grew, but the basic structure of federal enforcement actions remained the same. The starting point was the identifcation of a body of water with substandard water quality. After that, federal author- ities had to work backward and prove that a particular entity should be held responsible for the problem.7 Both the origi- nal version of the 1948 Act and all amendments enacted before 1972 proved to be ineffective due in part to this backward-looking model. See EPA v. California ex rel. State Water Resources Control Bd., 426 U. S. 200, 202 (1976). By 1972, the WPCA's inadequacy was apparent, and Con- gress made a fresh start. It amended the WPCA by delet- ing all its provisions and substituting what is now generally known as the Clean Water Act. The CWA jettisoned the WPCA's retrospective approach and aimed directly at the sources of pollution. A critical component of the CWA scheme is the National Pollutant Discharge Elimination Sys- tem (NPDES), see id., at 204–205, which makes it unlawful to discharge pollutants into covered bodies of water unless authorized by permit. Permits issued under this program may contain several different types of provisions. Some are known as “effuent limitations,” see 33 U. S. C. § 1311, which are defned as restrictions on the “quantities, rates, and concentrations of chemical, physical, biological, and other constituents.” § 1362(11). Section 1311(b)(1), subparagraphs (A) and (B), require compliance with one type of effuent limitations: those that are based on what can be achieved using specifed pollution-treatment technologies.

6 See Water Pollution Control Act Amendments of 1956, Pub. L. 84–660, 70 Stat. 498; Federal Water Pollution Control Act Amendments of 1961, Pub. L. 87–88, 75 Stat. 204; Water Quality Act of 1965, Pub. L. 89–234, 79 Stat. 903; Water Quality Improvement Act of 1970, Pub. L. 91–224, 84 Stat. 91. 7 See § 2(d), 62 Stat. 1156–1157; 70 Stat. 504–505; 75 Stat. 208–209; 79 Stat. 909. Cite as: 604 U. S. 334 (2025) 341

See 40 CFR § 122.44(a)(1) (2023). In most cases, these technology-based limitations are suffcient, but when they are not, NPDES permits also include water quality-based effuent limitations (WQBELs). 33 U. S. C. § 1311(b)(1)(C). These WQBELs, unlike technology-based effuent limita- tions, are “set without regard to cost or technology availabil- ity.” Natural Resources Defense Council v. EPA, 808 F. 3d 556, 565 (CA2 2015); see Natural Resources Defense Coun- cil, Inc. v. EPA, 859 F. 2d 156, 208 (CADC 1988) (per cu- riam). Instead, they permit only those discharges that may be made without unduly impairing water quality. In addition to these effuent limitations, it is common for permits to include requirements that do not set numerical limitations on allowed discharges. One example, which is apparently common in so-called general permits, is a provi- sion demanding that permittees follow certain “best prac- tices” that aim to limit pollution.8 Under the NPDES system, permittees have a very strong incentive to comply with all permit terms. For one thing, the CWA gives the EPA a very big “stick.” Permittees that do not comply may be hit with enormous civil penalties and may face criminal prosecution for “knowing” or even “negli- gent” violations. See §§ 1319(c) and (d); 40 CFR § 19.4 (2023). At the same time, the CWA holds out an enticing “carrot.” Under what is known as the “permit shield” pro- vision, an entity that adheres to the terms of its permit is deemed to be compliant with the Act. See 33 U. S. C. § 1342(k). B The case now before us involves a particular type of public wastewater treatment, one that processes both wastewater (water that has been used in a home) and stormwater (rain- water that does not sink into the ground). Many major

8 See Brief for National Association of Home Builders et al. as Amici Curiae 1, 11–12. 342 CITY AND COUNTY OF SAN FRANCISCO v. EPA

cities have such systems, and they present special problems. During periods of heavy precipitation, the combination of wastewater and stormwater may exceed the facility's treat- ment capacity, and the result may be the discharge of un- treated water, including raw sewage. See Combined Sewer Overfow (CSO) Control Policy, 59 Fed. Reg. 18689 (1994); EPA, Offce of Water, Combined Sewer Overfows: Guidance for Permit Writers, p. 1–1 (1995). This problematic feature of combined facilities was recognized long ago; installing a new system that handles stormwater and wastewater sepa- rately is enormously expensive.9 To address the problem of CSOs, the EPA adopted its CSO Control Policy, which requires municipalities with combined systems to take prescribed measures and to develop and im- plement a Long-Term Control Plan. 59 Fed. Reg. 18691. The CSO Policy provides for a two-phase permitting process. Id., at 18696. During phase I, permits require municipali- ties to implement nine minimum controls and to develop a long-term plan. Then, during phase II, that plan must be implemented. Ibid. In 2000, Congress amended the CWA and gave the CSO Control Policy the force of a statute. See 33 U. S. C. § 1342(q)(1). C The City of San Francisco operates two combined treat- ment facilities: the Bayside facility, which discharges into San Francisco Bay, and the Oceanside facility, which empties into the Pacifc Ocean. The permit at issue in this dispute concerns only the Oceanside facility,10 which treats water from 250 miles of sewers and serves approximately 250,000 residents. 75 F. 4th 1074, 1082 (CA9 2023). For many years, the Oceanside facility's NPDES permit was renewed without controversy, but in 2019, the two end-

9 T. Camp, The Problem of Separation in Planning Sewer Systems, 38 J. Water Pollution Control Federation 1959 (1966). 10 See App. to Pet. for Cert. 80–140. Cite as: 604 U. S. 334 (2025) 343

result requirements that San Francisco now challenges were added. Id., at 1084–1085. The frst of these prohibits the facility from making any discharge that “contribute[s] to a violation of any applicable water quality standard” for re- ceiving waters. Id., at 1085. The second provides that the City cannot perform any treatment or make any discharge that “create[s] pollution, contamination, or nuisance as de- fned by California Water Code section 13050.” Ibid. (inter- nal quotation marks omitted). The California Regional Water Quality Control Board for the San Francisco Bay Region approved the fnal Oceanside NPDES permit, and the EPA did the same.11 Id., at 1088. San Francisco appealed to the EPA's Environmental Appeals Board (EAB), objecting to, among other things, the two new provisions just noted. City and Cty. of San Francisco, 18 E. A. D. 322, 325 (2020). The EAB rejected San Francisco's challenge, and the City then fled a petition for review in the Ninth Circuit under 33 U. S. C. § 1369(b)(1)(F). 75 F. 4th, at 1088. A divided Ninth Circuit panel denied that petition, holding that § 1311(b)(1)(C) authorizes the EPA to impose “any” limitations that seek to ensure that applicable water quality standards are satisfed in a receiving body of water. Id., at 1089–1090. In dissent, Judge Collins argued that the CWA “draws an explicit distinction between the `limitations' that the agency must devise and impose on a particular per- mittee's discharges” and the water quality standards them- selves. Id., at 1102 (Collins, J., dissenting). The majority, he maintained, erred by making the “ `water quality stand- ards' themselves the applicable `limitation' for an individual discharger.” Ibid. We granted certiorari to decide whether the EPA can im- pose requirements like those at issue. 602 U. S. 1002 (2024). 11 Both the California Regional Water Quality Control Board and the EPA had to approve the NPDES permit because the Oceanside facility discharges into waters that fall under both state and federal jurisdiction. 75 F. 4th 1074, 1082 (CA9 2023) (case below). 344 CITY AND COUNTY OF SAN FRANCISCO v. EPA

II Contending that the Ninth Circuit misread § 1311(b)(1)(C), San Francisco leads with the argument that all “limitations” imposed under § 1311 must qualify as effuent limitations. The statutory text dooms this broad argument. “[W]here Congress includes particular language in one section of a statute but omits it in another section of the same Act, it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion.” Russello v. United States, 464 U. S. 16, 23 (1983) (internal quotation marks omitted). We have invoked this canon time and time again. See, e. g., Gallardo v. Marstiller, 596 U. S. 420, 429– 430 (2022); Salinas v. Railroad Retirement Bd., 592 U. S. 188, 196 (2021); Azar v. Allina Health Services, 587 U. S. 566, 576–577 (2019). And it is fatal to San Francisco's argument here. Sections 1311(b)(1)(A) and (B) refer to “effuent limi- tations,” but the very next provision, § 1311(b)(1)(C), re- fers instead to “any more stringent limitation.” We cannot believe that Congress omitted the term “effuent” from § 1311(b)(1)(C) simply because it wanted to save ink or as- sumed that regulators and interested parties would under- stand that the omission of the term was inconsequential. Other provisions of the CWA support this conclusion by describing § 1311 as authorizing the EPA to impose effuent or other limitations. See § 1341(d) (referring to “effuent limitations and other limitations, under section 1311”); § 1365(f) (referring to “effuent limitation[s] or other limita- tion[s] under section 1311”); § 1367(d) (same); see also Na- tional Assn. of Mfrs. v. Department of Defense, 583 U. S. 109, 122 (2018) (interpreting the phrase “effuent limitation or other limitation” in the CWA's judicial review provision, § 1369, to encompass both “effuent” limitations and limita- tions such as “non-numerical operational practice[s]” and “equipment specifcation[s]”). These reasons convince us that San Francisco's argument is wrong, but if more were needed, it is telling that the City's Cite as: 604 U. S. 334 (2025) 345

interpretation would lead to either drastic consequences that the City is unwilling to embrace or a very loose interpreta- tion of the term “effuent limitation” that would undermine the City's argument. As noted earlier, it is common for per- mits to contain “narrative” provisions requiring permittees to do such things as following certain “best practices.” These provisions do not directly restrict the “quantities, rates, or concentration” of pollutants that a permittee may discharge, and therefore they do not ft easily within the defnition of an “effuent limitation.” Nevertheless, the City acknowledges their legitimacy, see Brief for Petitioner 15, 33, n. 22, and if that is correct, it must follow either that (1) § 1311(b)(1)(C) authorizes the imposition of limitations other than effuent limitations (which would, of course, defeat the City's argument) or (2) the statutory defnition of an effuent limitation should be read very loosely (which raises the ques- tion why this broad interpretation would not encompass the provisions at issue here). Under either alternative, the City is on perilous ground. These problems overwhelm any help that the City can de- rive from the fact that § 1311 is titled “Effuent limitations.” The title of a statutory provision can inform its interpreta- tion, but it is not conclusive. See Dubin v. United States, 599 U. S. 110, 120–121 (2023). And here, the title of § 1311 is not enough to win the day for the City. Section 1311 is a lengthy provision, and most of its subsections concern effu- ent limitations. The title “Effuent limitations” provides a rough description of the provision's general sweep, but it cannot be read as doing more than that.

III In addition to the broad argument discussed above, San Francisco advances a narrower alternative, namely, that even if § 1311(b)(1)(C) is not limited to effuent limitations, it “does not authorize EPA to impose NPDES permit require- ments that condition permitholders' compliance on whether 346 CITY AND COUNTY OF SAN FRANCISCO v. EPA

receiving waters meet applicable water quality standards.” Brief for Petitioner 19. We agree with this argument. As the City maintains, “[t]he text, structure, and pre- and post- enactment context” support this interpretation. Ibid.

A We begin with the text of § 1311(b)(1)(C), which, as noted, requires a permit to contain, in addition to “effuent limita- tions,” “any more stringent limitation” that is “necessary to meet” certain “water quality standards” that are imposed under state law “or any other Federal law or regulation”; and “any more stringent limitation” that is “required to im- plement any applicable water quality standard established pursuant to this chapter.” (Emphasis added.) All the itali- cized terms in the preceding sentence suggest that the most natural reading of § 1311(b)(1)(C) is that it authorizes the EPA to set rules that a permittee must follow in order to achieve a desired result, namely, a certain degree of water quality. We start with the term “limitation.” As used in the rele- vant context, a limitation is a “restriction or restraint im- posed from without (as by law[ )].” Webster's Third New International Dictionary 1312 (1976) (emphasis added). A provision that tells a permittee that it must do certain spe- cifc things plainly qualifes as a limitation. Such a provision imposes a restriction “from without.” But when a provision simply tells a permittee that a particular end result must be achieved and that it is up to the permittee to fgure out what it should do, the direct source of restriction or restraint is the plan that the permittee imposes on itself for the purpose of avoiding future liability. In other words, the direct source of the restriction comes from within, not “from without.” We do not dispute that the term “limitation” is sometimes used in a looser sense, but our task is to ascertain what the term means in the specifc context in question. And here, Cite as: 604 U. S. 334 (2025) 347

our interpretation of the meaning of the term “limitation” in § 1311(b)(1)(C) must take into account the way in which the term is used in the two preceding statutory subsections, §§ 1311(b)(1)(A) and (B). In both those provisions, the “limi- tations” are imposed directly by the EPA, and it is therefore natural to presume that the term has a similar meaning in § 1311(b)(1)(C). See, e. g., McDonnell v. United States, 579 U. S. 550, 568–569 (2016); Yates v. United States, 574 U. S. 528, 544 (2015) (plurality opinion); A. Scalia & B. Garner, Reading Law 195–198 (2012). So the use of the term “limi- tation” in §§ 1311(b)(1)(A) and (B) provides an opening clue that the EPA's interpretation of § 1311(b)(1)(C) may be wrong. The terms “implement” and “meet” point in the same di- rection. The implementation of an objective generally re- fers to the taking of actions that are designed “to give prac- tical effect to and ensure of actual fulfllment by concrete measures.” Webster's Third New International Dictionary, at 1134. Section 1311(b)(1)(C) tells the EPA to impose re- quirements to “implement” water quality standards—that is, to “ensure” “by concrete measures” that they are “actual[ly]” “fulfll[ed].” Simply telling a permittee to ensure that the end result is reached is not a “concrete plan” for achieving the desired result. Such a directive simply states the de- sired result; it does not implement that result. Section 1311(b)(1)(C)'s other directive—that the EPA im- pose limitations that are “necessary to meet” certain water quality standards–is similar. The verb to “meet,” in the sense operative here, means “to comply with; fulfll; satisfy” or “to come into conformity with.” Random House Un- abridged Dictionary 1195 (2d ed. 1987). Thus, a limitation that is “necessary to meet” an objective is most naturally understood to mean a provision that sets out actions that must be taken to achieve the objective. In assessing what the directives in § 1131(b)(1)(C) mean, it is helpful to consider the use of the relevant terms in every- 348 CITY AND COUNTY OF SAN FRANCISCO v. EPA

day speech. Suppose a State requires that all schools “meet” certain standards of math profciency, and suppose the principal of a school calls a faculty meeting and instructs the teachers to “implement” those standards. The princi- pal's obvious expectation would be that the teachers would devise and “implement” a plan to make sure that the desired end is “met.” It is unlikely that the principal would be happy if the teachers simply told their students that a state math profciency test would be administered and that they should make sure they passed. That would not constitute the implementation of the desired end, i. e., meeting the State's standard of math profciency. Attempting to counter this interpretation, the EPA stresses § 1311(b)(1)(C)'s use of the term “any” in the phrase “any more stringent limitation,” arguing that “any” is a very broad term. That argument misconstrues the term's effect. The adjective “any” is indeed a broad term, but it cannot expand the reach of the noun it modifes. A reference to “any mammal” would capture all mammals, but it would not encompass a bird or fsh. Similarly, § 1311(b)(1)(C) encom- passes any limitation that is necessary to meet or implement water quality standards, but not provisions that do not fall within that category. B The text of the CWA militates against the Government's interpretation of § 1311(b)(1)(C) for yet another reason that stands out when the history of federal water pollution con- trol legislation is kept in mind. Under the Government's reading, a permittee may be held liable if the quality of the water into which it discharges pollutants fails to meet water quality standards. Before 1972, the WPCA contained a pro- vision that did exactly that in no uncertain terms. But when Congress overhauled the WPCA in 1972, it scrapped that provision and did not include in the new version of the Act anything remotely similar. Under these circumstances, the absence of a comparable provision in the CWA is telling. Cite as: 604 U. S. 334 (2025) 349

This glaring void resulted from a deliberate and prominent policy choice. As recounted earlier, before 1972, the basic structure of federal enforcement efforts was a lawsuit seek- ing to hold a polluter accountable for contributing to what amounted to or was expressly termed a violation of water quality standards. Building on the enforcement model orig- inally adopted in the 1948 Act, the 1965 amendments of the WPCA required the adoption of “water quality standards,” and they then provided that “violators” of these standards were subject to suit by the United States. 79 Stat. 907–909. That is where matters stood until 1972 when Congress again amended the WPCA by deleting its entire text and substitut- ing what is now popularly called the CWA. This overhaul of the WPCA continued to require the adop- tion of water standards, 33 U. S. C. § 1313, but the revised statutory text conspicuously omitted any provision authoriz- ing either the United States or any other party to bring suit against an entity whose discharges were contributing to a violation of those standards. This omission cannot be viewed as accidental or inconse- quential. The repealed enforcement provision went to the heart of what Congress viewed as a major defect in the old scheme. As we have noted, the 1972 overhaul aimed to facilitate enforcement by “making it unnecessary to work backward from an overpolluted body of water to determine which point sources [were] responsible” and thus subject to suit. EPA v. California, 426 U. S., at 204. Instead, the amended WPCA sought to achieve “acceptable quality stand- ards” by means of “direct restrictions” on polluters. Ibid. The Government's interpretation would undo what Congress plainly sought to achieve when it scrapped the WPCA's backward-looking approach.12 12 The dissent suggests that the 1972 Congress was displeased with the prior enforcement regime because it was too burdensome for the Govern- ment, not because it was unfair for entities against which enforce- ment actions were brought. See post, at 363–364 (Barrett, J., dissenting 350 CITY AND COUNTY OF SAN FRANCISCO v. EPA

C It is a “ `fundamental canon of statutory construction that the words of a statute must be read in their context and with a view to their place in the overall statutory scheme.' ” Utility Air Regulatory Group v. EPA, 573 U. S. 302, 320 (2014) (quoting FDA v. Brown & Williamson Tobacco Corp., 529 U. S. 120, 133 (2000)). Thus, in construing § 1311, we must also take into account the broader statutory scheme, and at least two features of that scheme point in favor of our interpretation. 1 The frst is the so-called “permit shield” provision, 33 U. S. C. § 1342(k), under which a permittee is deemed to be in compliance with the CWA if it follows all the terms in its permit. This protection is very valuable because violations of the CWA, even if entirely inadvertent, are subject to hefty penalties. The CWA imposes a regime of strict civil liabil- ity, see, e. g., United States v. Allegheny Ludlum Corp., 366 F. 3d 164, 174 (CA3 2004), and a party that violates a permit term may be fned up to $25,000 per day per violation, § 1319(d). As San Francisco explains, it may take months to gather the information necessary to detect a drop below the applicable water quality standards, see Tr. of Oral Arg. 16, and after substandard water quality is detected, it may take some time to devise and implement appropriate corrective measures. Indeed, there may be occasions (such as the multiple-discharger situation we discuss below, see infra, at 351–352), when there is nothing a permittee can do to bring about a prompt correction. For these reasons, the po- tential civil penalties for noncompliance can mount up and in part). But whether or not this assessment of Congress's intent is cor- rect, what matters for present purposes is that Congress deliberately de- leted a longstanding provision that expressly authorized what the dissent wishes to perpetuate. The idea that Congress sought to preserve the old enforcement mechanism by squirreling it away in § 1311(b)(1)(C)'s inapt language defes belief. Cite as: 604 U. S. 334 (2025) 351

reach enormous sums. In a pending suit against San Fran- cisco regarding the Bayside facility, the penalties sought are $10 billion. See Tr. of Oral Arg. 102. In addition to all this, a permittee who is found to have acted “knowingly” or even “negligently” may be criminally prosecuted. § 1319(c). Because of the harsh penalties for violating the terms of a permit, the permit shield is invaluable. Because of it, a discharger that complies with all permit conditions can rest assured that it will not be penalized. But the beneft of this provision would be eviscerated if the EPA could impose a permit provision making the permittee responsible for any drop in water quality below the accepted standard. A per- mittee could do everything required by all the other permit terms. It could devise a careful plan for protecting water quality, and it could diligently implement that plan. But if, in the end, the quality of the water in its receiving waters dropped below the applicable water quality levels, it would face dire potential consequences. It is therefore exceed- ingly hard to reconcile the Government's interpretation of § 1311(b)(1)(C) with the permit shield. And contrary to the Government's contention, the possibility that a court might ultimately exercise its “broad discretion” to mitigate penal- ties, see Brief for Respondent 44 (internal quotation marks omitted), is not enough to make up for disarming the shield.

2 One fnal structural feature cements the case against the EPA's interpretation: the absence of any provision dealing with the problem that arises when more than one permittee discharges into a body of water with substandard water qual- ity. As previously explained, it is hard to believe that the 1972 Congress used § 1311(b)(1)(C) to perpetuate (in camou- faged form) the backward-looking enforcement scheme in the prior version of the WPCA. And it is even harder to accept the proposition that Congress did that without setting out any method for dealing with the multiple-discharger prob- 352 CITY AND COUNTY OF SAN FRANCISCO v. EPA

lem. “[T]here may be dozens or even hundreds of . . . per- mitted and unpermitted discharges into the same water- body.” Brief for National Mining Association et al. as Amici Curiae 9. In such situations, the pre-1972 enforce- ment scheme made it necessary for federal authorities to “unscramble the polluted eggs after the fact.” Wilmington v. United States, 157 Fed. Cl. 705, 710 (2022). By 1972, it was recognized that this was impractical, yet the EPA main- tains that Congress retained the backward-looking approach without making any attempt to address the vexing multiple- discharger problem. The EPA's only response to this argument is to note that in this case the Oceanside facility is the only entity that discharges into the relevant area of the Pacifc Ocean. But the multiple-discharger problem goes to the meaning of § 1311(b)(1)(C), and that provision cannot mean one thing in a single-discharger case and another when there are multi- ple dischargers.13 IV Before concluding, we briefy address three additional arguments advanced by the Government. A The EPA maintains that the imposition of end-result limi- tations is the best course of action when “the information 13 In response to our arguments about the two structural features dis- cussed above, the dissent contends that our interpretation of § 1311(b) (1)(C) is not necessary to protect permittees because even without that interpretation a permittee subjected to an end-result provision could chal- lenge it as arbitrary and capricious. See post, at 364–366 (opinion of Bar- rett, J.). Of course, that response is no answer to our argument that § 1311(b)(1)(C) does not authorize end-result provisions in the frst place. And in any event, it is not clear that individual arbitrary-and-capricious challenges would provide adequate protection. Unless some form of judi- cial relief could be obtained before an end-result provision took effect, a permittee's potential liability could reach astronomical proportions before the challenge was fnally resolved. Cite as: 604 U. S. 334 (2025) 353

necessary to develop additional `effuent limitations' is un- available.” Brief for Respondent 41. And it complains that it should not bear the burden of determining what a permit- tee should do to protect water quality because a permittee is likely to have better access to necessary information and a superior understanding of the operation of its facility and the changes that could be made to provide further protection for water quality. We are not moved by this argument. For one thing, it appears that the EPA and state permitting authorities have used end-result requirements routinely, not just when a per- mit holder has failed to provide necessary information. See In re Lowell, 18 E. A. D. 115, 176 (EAB 2020); App. to Pet. for Cert. 519. And in any event, the EPA possesses the ex- pertise (which it regularly touts in litigation) and the re- sources necessary to determine what a permittee should do. It is also armed with ample tools to deal with situations in which a permittee is slow to provide needed information or is otherwise uncooperative. The EPA can set a schedule for the provision of information and can refuse to issue a permit until the permittee complies. If necessary, it can make use of its emergency powers. See 33 U. S. C. § 1364.14

B The EPA contends that Congress authorized the use of end-result requirements when it codifed the Agency's CSO Policy in 1994, see 33 U. S. C. § 1342(q)(1). And in support of that argument, it cites language in the policy that pertains

14 The dissent argues that end-result provisions are in the best interests of regulated entities because the alternative may be delay in the issuance of permits. Post, at 368 (opinion of Barrett, J.). If that were true, one would expect regulated parties to favor such provisions, but none has done so. On the contrary, a long list of municipalities and other permittees support San Francisco's position. See supra, at 338–339; infra, at 355. These sophisticated entities are better positioned than the dissent to judge what is good for them. 354 CITY AND COUNTY OF SAN FRANCISCO v. EPA

to phase I permits. But the permit in question here is a phase II permit, and the EPA does not claim that its inter- pretation is supported by any CSO Policy provision relating to such permits.15 In any event, the phase I language to which the EPA points does not authorize the imposition of end-result re- quirements. The policy states that a phase I permit should require a permittee to “[c]omply with applicable [water quality standards] expressed in the form of a narrative limi- tation.” 59 Fed. Reg. 18696 (emphasis added). Our deci- sion does not rule out “narrative limitations.” “Limita- tions,” as we understand the term, see supra, at 346–347, are permitted under § 1311(b)(1)(C), and limitations may be expressed in both numerical and non-numerical (i. e., “narra- tive”) form. Attempting to read more into the phase I language, the EPA cites guidance it issued in 1995, but Congress did not Page 15 Proof Pending Publication In fact, the CSO Control Policy specifes exactly what a phase II per- mit should contain, and those requirements are inconsistent with the end- result limitation that the EPA imposes here. Under the policy, a phase II should contain: (1) “[r]equirements to implement the technology-based controls”; (2) “[n]arrative requirements which insure [sic] that the selected CSO controls are implemented, operated and maintained as described in the long-term CSO control plan”; (3) “[w]ater quality-based effuent limita- tions . . . requiring, at a minimum, compliance with . . . numeric perform- ance standards for the selected CSO controls”; (4) “[a] requirement to im- plement, with an established schedule, the approved post-construction water quality assessment program”; (5) “[a] requirement to reassess over- fows to sensitive areas in those cases where elimination or relocation of the overfows is not physically possible and economically achievable”; (6) “[c]onditions establishing requirements for maximizing the treatment of wet weather fows”; and (7) “[a] reopener clause authorizing the NPDES authority to reopen and modify the permit upon determination that the CSO controls fail to meet [water quality standards] or protect designated uses.” 59 Fed. Reg. 18696. Again, although the purpose is to improve the quality of the relevant bodies of water, these permitting components all relate to the dischargers' behavior and the permitting authority's su- pervision of that behavior. Cite as: 604 U. S. 334 (2025) 355

codify that guidance, and we are not obligated to accept ad- ministrative guidance that conficts with the statutory lan- guage it purports to implement. See Loper Bright Enter- prises v. Raimondo, 603 U. S. 369 (2024). We also note that other guidance issued by the EPA is arguably inconsistent. See EPA, Combined Sewer Overfows: Guidance for Permit Writers, at A–1 to A–7. C Finally, the EPA contends that the rejection of its inter- pretation of 33 U. S. C. § 1311(b)(1)(C) would have disruptive consequences for businesses that rely on “general permits.” Brief for Respondent 38; Tr. of Oral Arg. 83. (General per- mits cover an entire category of point sources in a given area. See South Fla. Water Management Dist. v. Micco- sukee Tribe, 541 U. S. 95, 108, n. (2004).) Such permits are important for certain businesses, such as home builders, other construction companies, and certain agricultural enter- prises, see Brief for National Association of Home Builders et al. as Amici Curiae 1, 11, but no such company has sub- mitted a brief supporting the EPA's interpretation. On the contrary, a brief fled on behalf of such companies urges us to reject the EPA's position. Id., at 4–7. What is impor- tant, these companies tell us, are narrative limitations other than end-result requirements, and they specifcally cite pro- visions demanding compliance with “best-management prac- tices” and “operational requirements and prohibitions.” Our decision allows such requirements.

V In sum, we hold that § 1311(b)(1)(C) does not authorize the EPA to include “end-result” provisions in NPDES permits. Determining what steps a permittee must take to ensure that water quality standards are met is the EPA's responsi- bility, and Congress has given it the tools needed to make that determination. If the EPA does what the CWA de- mands, water quality will not suffer. 356 CITY AND COUNTY OF SAN FRANCISCO v. EPA

Barrett, J., dissenting in part

* * * The judgment of the Ninth Circuit is reversed.

It is so ordered. Justice Barrett, with whom Justice Sotomayor, Justice Kagan, and Justice Jackson join, dissenting in part. The Environmental Protection Agency issued San Fran- cisco a permit allowing it to discharge pollutants from its combined sewer system into the Pacifc Ocean. The permit, of course, does not give the city free rein, and among its conditions are prohibitions on discharges that contribute to a violation of applicable water quality standards. San Fran- cisco challenges these conditions on the ground that EPA lacks statutory authority to impose them. The city is wrong. The relevant provision of the Clean Water Act di- rects EPA to impose “any more stringent limitation” that is “necessary to meet . . . or required to implement any applica- ble water quality standard.” 33 U. S. C. § 1311(b)(1)(C). Conditions that forbid the city to violate water quality stand- ards are plainly “limitations” on the city's license to discharge. Notwithstanding the straightforward statutory language, the Court sides with San Francisco. I join Part II of its opinion, which rightly rejects the city's primary argument. In Part III, however, the Court embraces an equally weak theory—that the permit's restrictions are not “limitations,” as that word is ordinarily used. The Court's analysis is con- trary to the text, so I respectfully dissent in part.

I A Under the Clean Water Act, “the discharge of any pollut- ant by any person” is unlawful except as expressly author- ized. 33 U. S. C. § 1311(a). As relevant here, authorization Cite as: 604 U. S. 334 (2025) 357

comes in the form of “National Pollutant Discharge Elimina- tion System (NPDES) permits,” which EPA (or, in some cir- cumstances, a State) may issue to allow discharges. Before issuing a permit, however, the Agency must ensure that “such discharge will meet . . . all applicable requirements” under several different statutory provisions. § 1342(a)(1). Section 1311(b) is one such provision. It works in two steps for permits like San Francisco's. First, under § 1311(b)(1)(A), EPA must set “effuent limitations” that “shall require the application of the best practicable control technology currently available.” “ `[E]ffuent limitation' ” refers to a restriction “on quantities, rates, and concentra- tions of chemical, physical, biological, and other constituents which are discharged from point sources” into waters subject to EPA's jurisdiction. § 1362(11). Second, under § 1311(b)(1)(C), EPA must impose “any more stringent limitation, including those necessary to meet water quality standards, . . . or required to implement any applicable water quality standard.” Water quality standards—which are devised by the States and subject to federal approval—“consist of the designated uses of the navi- gable waters involved and the water quality criteria for such waters based upon such uses.” § 1313(c)(2)(A). Effuent limitations, standing alone, are not always suffcient to pro- tect the desired water quality, as set forth in the water qual- ity standards. So point sources, “ `despite individual compli- ance with effuent limitations, may be further regulated to prevent water quality from falling below acceptable levels.' ” Arkansas v. Oklahoma, 503 U. S. 91, 101 (1992) (quoting EPA v. California ex rel. State Water Resources Control Bd., 426 U. S. 200, 205, n. 12 (1976)). Importantly, the Act does not itself require dischargers to heed water quality standards; the standards are enforceable only insofar as they are incorporated into permit conditions under § 1311(b)(1)(C). Section 1311(b) therefore sets forth a coherent regime. In the frst instance, EPA regulates water pollution through 358 CITY AND COUNTY OF SAN FRANCISCO v. EPA

technology-based effuent limitations that restrict the “quan- tities, rates, and concentrations” of harmful materials that permittees may discharge. § 1362(11). But when the technology-based effuent limitations are insuffcient to en- sure that the water quality standards are met, EPA has sup- plemental authority to impose further limitations.

B As the Court explains, San Francisco operates a combined sewer system, which transports sewage and stormwater run- off via the same conduits. See ante, at 341–343. Such sys- tems occasionally overfow in wet weather—and when they do, they discharge both stormwater and untreated sewage into waters potentially regulated by the Clean Water Act. 59 Fed. Reg. 18689 (1994). As relevant here, “combined sewer overfow” events from one component of San Francis- co's sewer system result in the discharge of pollutants into the Pacifc Ocean via the Southwest Ocean Outfall, which is located within EPA's jurisdiction, 3.3 nautical miles off the coast of San Francisco. These discharges are presumptively unlawful under § 1311(a) and hence require a permit. The city's NPDES permit contains both the technology- based effuent limitations required by § 1311(b)(1)(A) and ad- ditional limitations to protect the water quality standards under § 1311(b)(1)(C). This latter category includes two “re- ceiving water limitations”—requirements defning the per- missible discharge by reference to its effect on the quality of the waters that receive it, rather than by reference to the nature of the discharge itself. (These are what the Court calls “ `end-result' requirements.” Ante, at 338.) The frst states that San Francisco “shall not cause or contribute to a violation of any applicable water quality standard.” App. to Pet. for Cert. 97. The second provides that “[n]either the treatment nor the discharge of pollutants shall create pollu- tion, contamination, or nuisance” as defned by the California Water Code. Id., at 339. Cite as: 604 U. S. 334 (2025) 359

The city's permit thus tracks the structure of § 1311(b). It restrains discharges initially through technology-based ef- fuent limitations, as required by § 1311(b)(1)(A). But be- cause the effuent limitations may be insuffcient to ensure that California's water quality standards are met, the permit contains supplemental limitations, as required by § 1311(b) (1)(C). The concern that the technology-based effuent limi- tations may fall short is on display in this case—discharges from components of San Francisco's sewer system have al- legedly led to serious breaches of the water quality stand- ards, such as “discoloration, scum, and foating material, including toilet paper, in Mission Creek. ” Complaint in United States v. City and County of San Francisco, No. 3:24–cv–02594 (ND Cal., May 1, 2024), ECF Doc. 1, p. 22. The receiving water limitations imposed under § 1311(b) (1)(C) are included to ensure that such breaches do not occur.

II Page Proof Pending A Publication San Francisco dedicates almost all its briefng to the prop- osition that the receiving water limitations are unlawful be- cause § 1311(b)(1)(C) allows only effuent limitations. In other words, San Francisco reads the phrase “any more stringent limitation” to mean “any more stringent effuent limitation.” As the Court explains, this argument is fatly inconsistent with the text of § 1311(b). See ante, at 344–345. In my view, the failure of that argument should have ended this case. The Court continues, however, with a theory largely of its own making. Whatever “any more stringent limitation” may mean, the Court says, it does not authorize EPA to di- rect permittees to comply with the water quality standards. This conclusion is puzzling. The entire function of § 1311(b)(1)(C) is to ensure that permitted discharges do not violate state water quality standards. And as discussed above, the provision gives EPA broad authority to achieve 360 CITY AND COUNTY OF SAN FRANCISCO v. EPA

that aim through conditions imposed in NPDES permits. Why would that broad authority not allow EPA to tell per- mittees that they must not cause or contribute to a viola- tion of the very standards that § 1311(b)(1)(C) serves to safeguard? The answer, according to the Court, is that a restriction does not count as a “limitation” if the permittee must iden- tify the steps necessary to comply with it. Ante, at 346. San Francisco's permit only authorizes discharges that do not degrade water quality below the applicable standard. It is up to the city, however, to formulate a plan to achieve that result. The city's plan, the Court asserts, is a “limitation” on its discharges, but the permit condition is not. See ibid. As best I can tell, the Court thinks that only the “direct source of restriction or restraint”—apparently, the most spe- cifc restriction—counts as a “limitation.” Ibid. The Court offers nothing to substantiate this proposition, and it is wrong as a matter of ordinary English. It is com- monplace for “limitations” to state “that a particular end re- sult must be achieved and that it is up to the [recipient] to fgure out what it should do.” Ibid. For example, a com- pany could impose spending “limitations” by requiring each branch to spend no more than its allotted budget, while still leaving branch managers fexibility to determine how to allo- cate those funds. A doctor could impose a “limitation” on a patient's diet by telling the patient that she must lose 20 pounds over the next six months, even if the doctor does not prescribe a specifc diet and exercise regimen. And an air- line could impose a “limitation” on the weight of checked bags, even though it does not tell passengers what items to pack. “Limitations” can be general as well as specifc, and general limitations can call for more specifc ones. In this context, “limitation” is simply a synonym for “[a] restrictive condition.” Funk & Wagnalls New Standard Dictionary of the English Language 1437 (1952). And condi- tions can be stated at many levels of generality—including Cite as: 604 U. S. 334 (2025) 361

in terms of end results. A college may condition a scholar- ship on the student's maintenance of a minimum GPA. A homeowner may condition payment for a new roof on the contractor's satisfaction of industry standards. An em- ployer may condition job perks on the employee's perform- ance. In each example, the condition is a limitation on a beneft or payment. There are strings attached. The Court also misconstrues § 1311(b)(1)(C)'s reference to limitations that are “necessary to meet” or “required to im- plement” the water quality standards. As for the former phrase, “necessary to meet” does not imply anything about the specifcity or concreteness of the limitations adopted by EPA. Rather, the limitations on San Francisco's permit are “necessary to meet” the water quality standards because without them, the standards would not bind the city. The limitations thus ensure that San Francisco will “ `comply with,' ” “ `fulfll,' ” “ `satisfy,' ” or “ `come into conformity with' ” the water quality standards. Ante, at 347 (quoting Random House Unabridged Dictionary 1195 (2d ed. 1987)). Nor does the phrase “required to implement” help the Court. “Implement,” the Court says, generally means “ `to give practical effect to and ensure of actual fulfllment by concrete measures.' ” Ante, at 347. That is true but incom- plete. The full defnition reads: “to carry out: accomplish, fulll, . . . esp: to give practical effect to and ensure of actual fulfllment by concrete measures.” Webster's Third New International Dictionary 1134 (1976). So while the word is often used in the sense of taking “concrete meas- ures,” such measures are not necessary to satisfy the defni- tion of “implement.” Regardless, the receiving water limitations “implement” the water quality standards in both the broad and narrow senses of the word. They are required to “carry out[,] ac- complish, [or] fulfll” the standards: When effuent limitations fall short, discharges from the city's combined sewer system will otherwise degrade water quality below the applicable 362 CITY AND COUNTY OF SAN FRANCISCO v. EPA

standard. Ibid. (capitalization altered). And the limita- tions are “concrete measures,” ibid., because they are the means by which EPA “implement[s] any applicable water quality standard,” § 1311(b)(1)(C). They give the standards “practical effect” by making them enforceable. Id., at 1134. There is no getting around it: The receiving water limita- tions are “limitations.” If they are vague or unreasonable, they are vulnerable to challenge on one or both of those grounds. See, e. g., Natural Resources Defense Council v. EPA, 808 F. 3d 556, 578 (CA2 2015) (invalidating a receiving water limitation as arbitrary and capricious). But even a vague or unreasonable limitation is still a “limitation.”

B With the text of § 1311(b)(1)(C) against it, the Court tries to marshal support for its approach from the Clean Water Act's history, as well as from what the Court describes as the “broader statutory scheme.” Ante, at 348–352. Nei- ther helps. 1 As for the statutory history: Advancing a specifc theory of the congressional intent behind the Clean Water Act, the Court contends that EPA's interpretation would revive the “backward-looking” policy regime that the Act was designed to replace. See ante, at 348–349. Before the Act, the United States enforced federal water pollution laws primar- ily through abatement actions. See 33 U. S. C. § 1160 (1970 ed.). Though the Act abolished this cause of action, the Court claims that receiving water limitations function in es- sentially the same way. Just as the United States did when it brought abatement suits, EPA would have to “ `work back- ward from an overpolluted body of water' ” to combat water pollution. Ante, at 349 (quoting State Water Resources Con- trol Bd., 426 U. S., at 204). Thus, the Court insists, the use of receiving water limitations would “undo” the Act's shift from abatement suits to “ `direct restrictions' on polluters.” Cite as: 604 U. S. 334 (2025) 363

Ante, at 349 (quoting State Water Resources Control Bd., 426 U. S., at 204). Of course, no theory of “what Congress plainly sought to achieve,” ante, at 349, could justify an implausible interpre- tation of § 1311(b)(1)(C). Here, however, the Court does not even deliver on the claim that its account “plainly” tracks Congress's goal. Ante, at 349. Because receiving water limitations do not actually replicate the old abatement re- gime, the Court's rendition is not the only (much less the most obvious) explanation for the statutory before and after. There is another explanation, and it is one in which receiving water limitations ft right in. Under the old system, the United States could bring abatement actions only after the pollution had already oc- curred. See 33 U. S. C. § 1160(c)(5) (1970 ed.). A glaring problem with this approach is that an ex post enforcement regime does not adequately deter polluters or prevent pollu- tion. Making matters worse, this regime involved “cum- brous enforcement procedures” that made it next to impossi- ble to bring abatement actions. State Water Resources Control Bd., 426 U. S., at 202; see also 33 U. S. C. § 1160 (1970 ed.) (requiring, prior to an abatement action, that the United States hold a conference of the relevant state agencies, then provide the state agency six months to take remedial action, then call a public hearing with the state agency and the discharger); K. Murchison, Learning From More Than Five-and-a-Half Decades of Federal Water Pollution Control Legislation: Twenty Lessons for the Future, 32 Boston Col- lege Env. Aff. L. Rev. 527, 534 (2005) (“According to a report prepared by the Senate Committee on Public Works, the fed- eral government initiated only one enforcement action under the Federal Water Pollution Control Act prior to 1970”). Congress chose a different regulatory model when it adopted the Act in 1972. The Act renders all discharges presumptively unlawful. Then, under the current ex ante permitting regime, EPA authorizes only those discharges 364 CITY AND COUNTY OF SAN FRANCISCO v. EPA

that comply with the Act. Should a permittee fail to comply with the terms of its permit, EPA has broad authority to sue. See 33 U. S. C. §§ 1319(b)–(d) (authorizing civil actions for injunctive relief, civil penalties for violations, and in some instances criminal sanctions). The receiving water limitations imposed under § 1311(b) (1)(C) are entirely consistent with this scheme. Again, the technology-based effluent limitations imposed under § 1311(b)(1)(A) do the primary work of gating discharges at the front end to minimize pollution. The § 1311(b)(1)(C) lim- itations guard against any residual risk that discharges will violate the water quality standards. Because these limita- tions supplement rather than replace the technology-based effuent limitations, there is no risk that broadly worded re- ceiving water limitations will recreate the ineffective abate- ment regime that prevailed prior to 1972. Furthermore, the receiving water limitations operate within the broader context of the Act's permitting regime. These permits impose a prospective requirement on permit- tees to comply with permit conditions. Under the old re- gime, a discharger could take an approach of “pollute frst and apologize later,” secure in the knowledge that an abate- ment suit was unlikely and that such a suit would at most allow judgment to “secur[e] abatement of any pollution proved.” 33 U. S. C. § 1160(h) (1970 ed.). A permittee who violates a permit condition, by contrast, necessarily exposes itself to enforcement actions by EPA, as well as potential penalties. See 33 U. S. C. §§ 1319(b)–(d). Receiving water limitations, like any other permit condition, thus operate as “ `direct restrictions' on polluters.” Ante, at 349 (quoting State Water Resources Control Bd., 426 U. S., at 204).

2 The Court also claims that the receiving water limitations are inconsistent with two features of the “broader statutory scheme.” Ante, at 350–352. First, it contends that the re- Cite as: 604 U. S. 334 (2025) 365

ceiving water limitations are at odds with the permit shield provision because violations of the permit condition (and the attendant liability) are hard to predict. Ante, at 350–351. Second, it argues that the Clean Water Act is silent about the problem of multiple dischargers into the same body of water—and if the Act allowed EPA to condition a permit on maintaining water quality standards, the Court says, it surely would have spelled out how to deal with such an obvi- ous complication. Ante, at 351–352. Both of these argu- ments boil down to the Court's concern that receiving water limitations might be unfair to permittees. In some circum- stances, they might be. But any unfairness should be ad- dressed through arbitrary-and-capricious challenges—not a statutory rewrite. Start with the permit shield provision. Under § 1342(k), compliance with the terms of a permit “shall be deemed com- pliance” with various substantive provisions of the Act, thereby shielding permit holders from liability. The Court insists that receiving water limitations like those in the city's permit would “eviscerat[e]” that beneft by failing to provide fair notice. Ante, at 350–351. The permit shield provision, however, serves the specifc role of immunizing permittees that comply with a permit. See § 1342(k). For instance, it “insulate[s] permit holders from changes in various regulations during the period of a permit” and “relieve[s] them of having to litigate in an en- forcement action the question whether their permits are suf- fciently strict.” E. I. du Pont de Nemours & Co. v. Train, 430 U. S. 112, 138, n. 28 (1977). The receiving water limita- tions do not eliminate that beneft. It remains true that San Francisco cannot be sued under the theory that the city's permit is insuffcient to ensure compliance with the Act. Really, the Court's argument reduces to the broader policy concern that it may be diffcult for regulated entities to com- ply with receiving water limitations and that they may lack adequate notice of a violation. But again, that concern goes 366 CITY AND COUNTY OF SAN FRANCISCO v. EPA

to the question whether a particular receiving water limita- tion is rational. If a permittee cannot reasonably determine how to comply with a receiving water limitation, then the permit condition may be invalidated as arbitrary and capri- cious. (In fact, San Francisco made arbitrary-and- capricious arguments below, but the Ninth Circuit rejected them; the city did not seek this Court's review of that issue. See 75 F. 4th 1074, 1092–1093 (2023).) And as EPA acknowl- edged at oral argument, the Agency “may not impose limita- tions of any kind that are unconstitutionally vague.” Tr. of Oral Arg. 51. These concerns do not speak to the relevant question here, which is whether receiving water limitations comport with the Act. The Court is also wrong to suggest that receiving water limitations are categorically impermissible because there may be multiple dischargers into one body of water in some circumstances. See ante, at 351–352. It makes little sense to say that an agency always lacks authority to take a cer- tain action just because the action would be unreasonable in some scenarios. And as the Court itself recognizes, there is no multiple-discharger problem here: San Francisco is the only signifcant discharger at the Southwest Ocean Outfall. Ante, at 352. If EPA does start imposing receiving water limitations in contexts where permittees cannot control the quality of the receiving waters—such as where there are multiple dischargers—then, again, the permittee can bring an arbitrary-and-capricious challenge.

3 Finally, the Court downplays the valuable uses of receiv- ing water limitations. To begin, EPA imposes such limita- tions when the Agency “lacks the information necessary to develop more tailored limitations.” Tr. of Oral Arg. 51. That is the case here: San Francisco has consistently failed to update its Long-Term Control Plan for managing com- bined sewer overfows. See 75 F. 4th, at 1095 (observing Cite as: 604 U. S. 334 (2025) 367

that San Francisco has not updated its plan since 1991). By imposing receiving water limitations, EPA was nevertheless able to issue a permit to San Francisco while complying with the Clean Water Act. The Court does not explain what other course of action EPA could take. Instead, it states, without citation, that “EPA possesses the expertise . . . and the resources neces- sary to determine what a permittee should do.” Ante, at 353. This bare assertion simply ignores the obvious problem—how is EPA expected to deploy its expertise when it lacks the basic information necessary to make a decision? The Court also suggests that the Agency could refuse to issue a permit until the applicant provides the necessary in- formation. Ibid. But this gives the game away: The entire point of EPA's argument is that it is preferable for EPA to impose broadly worded conditions in its permits than to deny permits altogether and potentially shut down San Francisco's sewer system. Nor can EPA simply “make use of its emer- gency powers” when permittees fail to provide necessary in- formation. Ibid. Such powers are available only when there is “imminent and substantial endangerment to the health of persons or to . . . the livelihood of . . . persons.” § 1364(a). As the name “emergency” suggests, these powers provide a limited avenue for the Agency to sue in response to a crisis. They do not provide a solution to the problem of noncompliant permittees. Receiving water limitations are also useful when EPA is- sues general permits to broad categories of dischargers (such as for construction projects). See South Fla. Water Man- agement Dist. v. Miccosukee Tribe, 541 U. S. 95, 108, n. (2004) (observing that such “permits greatly reduce . . . administra- tive burden by authorizing discharges from a category of point sources within a specifed geographic area”). In lieu of individualized and prescriptive permitting conditions— which would take time to craft and with which small busi- nesses might have diffculty complying—EPA instead allows 368 CITY AND COUNTY OF SAN FRANCISCO v. EPA

the permittee to proceed under more general language. EPA can therefore issue the permit quickly and give respon- sible permittees fexibility to choose how to comply with the permit. After today, the alternative for entities seeking a general permit is not for EPA to issue the permit without the § 1311(b)(1)(C) limitation. Instead, the alternative is for the permit to be delayed or even denied. See Tr. of Oral Arg. 83 (If the Court “take[s] away [EPA's] ability to rely on these sorts of prohibitions,” then the Agency is “going to need to ask for more information because it's only with that informa- tion” that the Agency can “develop more tailored limita- tions”). Section 1311(b)(1)(C) is not optional; EPA is re- quired to issue the limitations necessary to ensure that the water quality standards are met. So taking a tool away from EPA may make it harder for the Agency to issue the permits that municipalities and businesses need in order for their discharges to be lawful. The Court dismisses this concern, noting that “no . . . com- pany has submitted a brief supporting . . . EPA's interpreta- tion.” Ante, at 355. But there is no reason to think that the sampling of trade associations from which this Court happens to hear refects the views of all potentially affected parties. And in any event, neither the cited amicus brief nor the Court itself has any response to EPA's straightfor- ward point: If the Agency must impose individualized condi- tions for each permittee under § 1311(b)(1)(C), then it will be more diffcult and more time consuming for the Agency to issue permits. * * * Receiving water limitations are not categorically incon- sistent with the Clean Water Act. Because the Court holds otherwise, I respectfully dissent in part. Reporter’s Note

The attached opinion has been revised to refect the usual publication and citation style of the United States Reports. The revised pagination makes available the offcial United States Reports citation in advance of publication. The syllabus has been prepared by the Reporter of Decisions for the convenience of the reader and constitutes no part of the opinion of the Court. A list of counsel who argued or fled briefs in this case, and who were members of the bar of this Court at the time this case was argued, has been inserted following the syllabus. Other revisions may include adjustments to formatting, captions, citation form, and any errant punctuation. The following additional edits were made:

p. 334, line 1: “1151” is changed to “1251” p. 335, line 10: “the” is inserted before “EPA” p. 335, line 12: “the” is inserted before “EPA” p. 335, line 6 from bottom: “the” is inserted before “EPA” p. 336, line 29: “and remanded” is deleted p. 339, line 8: “Boston College” is inserted before “Env.” p. 350, n. 12, line 5: “§ 1311(b)(1)(B)” is replaced with “§ 1311(b)(1)(C)” p. 363, line 9 from bottom: “Boston College” is inserted before “Env.” p. 363, line 9 from bottom: “L. Rev.” is inserted after “Aff.”